Engine exhaust muffler



Sept. 8, 1959 M. o. MILLER ENGINE EXHAUST MUFFLER Filed July 6, 1954 INVENTOR. MERAL O. MILLER United States Patent ENGINE EXHAUST MUFFLER Meral 0. Miller, San Diego, Calif., assignor of fifty percent to James L. Matheny, Santa Ana, twenty-five percent to Thomas Ralph Snider, Orange County, and one percent to Western Inventors, San Diego, Calif., a corporation of California Application July 6, 1954, Serial No. 441,487

1 Claim. (Cl. 18147) The present invention relates generally to combustion engines and more particularly to an engine exhaust muffier.

The primary object of this invention is to provide an exhaust muffler having a novel arrangement of flow deflecting baifles which direct exhaust gases so as to create pressure pockets surrounding the main exhaust stream to absorb the vibrations caused by the pulsations of the engine exhaust.

Another object of this invention is to provide an exhaust muifier in which deflected portions of the exhaust gases are returned substantially at right angles to the main exhaust stream to interfere with and to nullify any tendency for establishment of vibration patterns in the main exhaust stream, which would otherwise become cumulative axially of the mufller as the gases progress along its length.

Another object of this invention is to provide an exhaust muflier in which secondary combustion is initiated to reduce the noxious contents of the exhaust gases.

Another object of this invention is to provide an exhaust mufiier in which the major portion of the exhaust stream has an unrestricted flow through the muflier, thus reducing back pressure to a minimum.

Another object of this invention is to provide an exhaust mufller which is inexpensive and practicable to manufacture.

Finally, it is an object to provide an exhaust mufller of the aforementioned character which is simple, safe and convenient to use, and which will give generally efficient and durable service.

With these and other objects definitely in view, this invention consists in the novel construction, combination and arrangement of elements and portions as will be hereinafter fully described in the specification, particularly pointed out in the claim and illustrated in the drawing which forms a material part of this disclosure and wherein similar characters of reference indicate similar or identical elements and portions throughout the specification and throughout the views of the drawing, and in which:

Fig. 1 is a perspective view, partially cut away, of the mufliler.

Fig. 2 is a longitudinal sectional view thereof taken on the line 22 of Fig. 1.

Referring now to the drawing in detail, the muflier comprises a cylindrical casing having end plates 12 and 14. Fitted in the end plate 12 is an inlet pipe 16 and extending through the end plate 14 is an outlet pipe 18.

Longitudinally spaced within the casing '10 are a plu rality of baflles 20, each comprising a baifle disc 22 having a central stub pipe 24 extending from one side there of. The stub pipes 24 all extend toward the inlet pipe 16 and are in axial alignment with said inlet pipe and the outlet pipe 18. The inwardly projecting end of the outlet pipe 18 provides a further stub pipe 26, the end plate 14 constituting the baflle disc in this instance. The baflles 20 thus divide the muffler into a plurality of an- 2,903,085 Patented Sept. 8, 1959 nular baflle chambers 28 defined between the casing 10 and the stub pipes 24.

The muflier is installed in the exhaust system of an engine in the normal manner, the direction of flow of the gases through the mufller being indicated by arrows in Fig. 2. It will be evident that the greater portion of the exhaust gases flows straight through the axially aligned stub pipes 24 and 26 and are expelled through the outlet pipe 18. Since the exhaust gases are under considerable pressure, a portion of the gases expands and is deflected into the baffle chambers 28 by the stub pipes 24. A portion of the gases are initially deflected by the stub pipes and swirled in the bafile chambers 28, as shown by the directional arrows and, upon further deflection by the upstream baflles re-enter the main exhaust stream substantially at right angles thereto. This, together with the cushioning effect of the annular pockets of swirling gases, effectively subdues the resonant effect of the exhaust stream, so reducing the noise and vibration thereof.

By way of further explanation, the exhaust stream actually consists of a plurality of slugs of compressed gases travelling in succession through the mufller and having a vibration or pulsation of a particular frequency or wavelength relative to the operating speed of the associated engine. It is most unlikely that the wavelength, or he effective length of each slug of gases, is exactly equal to the spacing of the baflles 20, thus the re-entering gases from the baflie chambers 28 strike the successive slugs at different phases of their pulsations as they pass through each bafl'le stage. The end result is that the natural pulsation of the exhaust is broken up and consequently subdued by the ofl-frequency cushioning eflect of the pressure pockets in the bafiie chambers 28. In this manner, sympathetic or harmonic vibration of the mufiier with the exhaust stream is prevented.

The re-entry of the gases from the baflie chambers 28 into the main exhaust stream causes considerable mixing of the gases, with the result that further oxidation of the gases takes place. The temperature of the exhaust gases is normally suificiently high to encourage such oxidation, and a certain quantity of oxygen in available form is present since combustion is usually incomplete in many engines. Thus much of the poisonous carbon monoxide in exhaust gases may be further oxidized to carbon dioxide by this action while smoke, sludge and unwanted odors in the exhaust are reduced.

The operation of this invention will be clearly comprehended from a consideration of the foregoing descrip-' tion of the mechanical details thereof, taken in connection with the drawing and the above recited objects. It will be obvious that all said objects are amply achieved by this invention.

Further description would appear unnecessary.

It is understood that minor variation from the form of the invention disclosed herein may be made Without departure from the spirit and scope of the invention, and the specification and drawing are to be considered as merely illustrative rather than limiting.

I claim:

An engine exhaust mufller comprising a cylindrical casing having an inlet and an outlet, a plurality of longitudinally spaced flat, transverse baflles in said casing, the spacing of said baffies being equal, each of said baflles including a disc having an aperture and an imperforate stub pipe secured in said aperture and projecting from the upstream side only of the disc, said stub pipes being axially aligned with said inlet and outlet to provide a linear passage therethrough for exhaust gases, said stub pipes, inlet and outlet having a diameter approximately one-half the diameter of the casing so that the greater portion of the exhaust gases flow straight through the axially aligned stub pipes while minor portions are initial- 1y radially outwardly deflected, said bafiles being means to deflect all of said minor portions radially inwardly of the casing to re-enter the main exhaust stream substantially at right angles thereto, said stub pipes, baflles and casing generally defining annular chambers of equal dimension measured axially of the casing, and each annular chamber including a pressure pocket defined radially outwardly of the corresponding stub pipe, said pressure pockets having a cushioning effect on said minor portions.

References Cited in the file of this patent UNITED STATES PATENTS 

